Telegrapone.



`nativa 'n.fs'fiiianr, or` "WHEELING, Wnsr VIRGINIA FIQE.

, 'f TELEGRAPHONE.

- Application' filed September To alt whom it may'concern.:` Be it known that I, HARVE'R. STUART; a citizen of the United States, -residing at Wheeling, in the-county of Ohio and State of 5A West Vir inia, have invented certain new A and useiu Im rovements in Telegraphones,

oi which the fo lowing is a full, clear, and eX- I- act description. V

My invention relates to apparatus for magnetically recording Vand reproducing sound and commonly known as the telegraphone.

'lfhe present invention covers particularly an improvement in the-circuits of the telegi ra hone apparatus by which improved resu ts are obtained in recording arid repro- `ducing sound or any other vibrations.V In telegraphones, as ordinarily used, a steel disk or recording medium is `continu-y ously moved in close proximity or contact with a magnet or magnets forming part of a telephone circuit. When the recording magnet is in a transmitting telephone circuit, a magnetic record is made on thecontinuously moving medium, and this record is repro- '25 duced at any subsequent time when the machine is operated with the recording magnet in a receiving telephoneA circuit. When the machine isrecording, the steel Aof the record-` 'ing medium is magnetized'under V,the influenceof the magnetic fluctuations in the recording magnet and during the reproduction Athis magnet is caused to undergo the same magnetic pulsations which are converted into electric pulsations in; the receiving-telephone circuit. From a theoretical sta-ndpoint the action is quite complex and "inv volves many electric and magnetic phenomena. Amon such phenomena are hysteresis eiiects or osses in the core ofthe recording ma steel o the recording medium. It 'is desirable 'to reduce these losses as much as possible, and -my experiments have been di.

vrected to-"fi'ccomplishin this result.

In my experiments rhave discovered -sults y the use of a condenser connected in circuit with a battery and with the recording and reproducing magnet in a specialrnanner.4 It is my theory ofthe operationthat thecondenser serves to change the relation or proportion between the current pulsationsin one'direction and those in the other through the recording andreproducing magnet, 'and that this is accompanied by a correspond-.'- ingly dierent character in `the 'changing 1 Specification f Letters Patent.

et, and particularly in the hardened that* it is ossible to attain greatly improved re-f Patented July i4, 190s.

24, i901. serial N. 394,294.

vin the recording and vreproducing medium. It aappears that if the vmagnetic fluctuations can e caused in any way to have about equal values of first north and then south polarity,

on'the recording 'medium will represent-the largest 'possible intensity variation, corre-` spending to the'maximum efliciency of re-1 production. `While this is .my theory ofthe retical principles of the circuits when the ing a record.; Fig. 3 is a view similar to 2 showing the essential features of a modified reproducing relation.,

' Referring to the drawings, and particumitter, and 2 a battery in a circuit including the' primary 3, of an induction coil;

is adalted to be connected to a recording and repro .ucing magnet 5, by any suitable means (such as-a switch laterdescribed). The cir- `'tion No'. I in Fig. 2. en the circuits are changed for the reproducing-operation the 4magnet 5 is connected. to a telephone receiver 6, as shown at switch position No..II in Fi 2 These circuits and arrangements thus Iar described are of the ordinary sort in telegraphone apparatus. 4

I provide a condenser 7, one side of which is 'directly connected to a battery 8, so that the in series withone another. ed terminals of the condenser andthe battery-.are`put-in abridging or shunt circuit 5. The result of this arrangement is to -IinagneticV conditions inthe pole thereof and 'that' the degree of changing magnetization shows diagrammatically the essential theolarly to Fig. 2 thereof, 1 indicates a trans-l -fIn accordance with the present invention operation, 'I believe that it is not quite cermachine is recording andwhen it is reproducarrangement of the circuits'in recording and 4 indicates the secondary of the @on which cuits at this time corres ond to switch posicondenserand the battery 'may be said to be j The unconnectabout the recording or reproducing magnet improve the strength and clearness-ofw :theiecord reproduction. .Infthisl action the condenser .has anormal charge correspondf ing to. the'voltage ofthe battery; so that the current -fluctuations fof the telephone circuit WhGhare impressed on-` the condenser have to be superposed on this charge'. It isf-clear that the current pulsations of af'd'irection tending to diminish the normal charge of the vcondenser will be more powerful'than those which tend to still further increase the potenv .tial of the condenser against the counter E. M. F. of the charge already accumulated therein. The character of thel current Waves will therefore be changed from their normal characteristics-inthecondenser circuit, and

.this obviously plroduces an inverse 'change in the circuit of t 1 magnet 5 which is in multiple with the conerecording and reproducing denser circuit. l In other words, the positive andnegative current values in the magnet 5 will be displaced with respect'to the central or zero` line of'curren'ty llow..` This shifting lof the current Waves with respect to the .zero

.line in the magnet 5`isl accompanied bya cor-.

responding change in the magnetizing action on the recording medium, with an inprovement in efficiency, as already indicated.

In Fig. 3 the same apparatus and parts are employed with substantially the same circuit arrangements, except that the-talking bat= tery 2 is made use of fornormallycharging.-

the condenser 7 4in place of the special battery 8.` There is no reason why the battery v 2 should not be made to'serve this purpose vsince it does not interfere `in an wa with its regular function. This can be easily accomplished by a connection 9, from one terminal thereof, the other terminal beingconnected to the other side of the condenser o through, a wire 10, and through the secondary 4 of the induction coil. These connec# tions do not disturb the regular function of the battery 2 in impressing a. current.

are shown denominated in the same way as in Figs. 2 and 3. 12 indicates a switch having blades 12a, 12b, 12 and 12d. These blades-.are arranged and connected in such a way that in the normal position of the switch the blades 12*1 and 12b are in electrical contact `with one another, butin the alternate position of the switch corresponding to the recording operation of the machine the blades 12a and 12b are separated, while 12b,

-ing a record, ther switch 12 is mvedto the alternate position ofthat shown, and a circuit is completedfrom the .battery 2, through wire '.Z, blade-12F1`,to.blade 12., Aand from ter 1,'wirel Z4, primary winding 3, ba'ck to b attery .The voice currents l in this circuit under the influence of the transmitter induce currents inffthe sec ondary winding 4, which traverses the following circuit: wire m, .blade 12C, blade 129, -wire Z2, magnet 5, wire .m2, switch l'wire m3,back to the secondary *4. This circuit. includes secondary 4, and

recording' and reproducingmagnet 5, as required, so that the record is properly made on the recording medium. At the same time the erasing magnet 414v is constantly energized from the battery inadvance of the recording and'reproducing-magnet by the following circuit: battery 2, wire Z', blade 12d,

blade 12. blade 12b, vwire Z2, wire a', magnet.,

14, wire fn?, back to the battery. The condenser 7 is connected vin series with the'battory and bridged across the recording andreproducing magnet 5 at this time as follows: Condenser 7. wirec, battery 2, wire Z', blades 12d, `12", wire m', winding 4, and wire o2, back to -the condenser. Inasmuch as the magnet 5 `is connected to Ithe freeterm'inal of the batteryat the 'blade l1.2l ,'and to the free terminal of the condenser by the wire m3, at

thisy time, it is evident that the condenser and battery are in series with one, another, and together bridged or shunted across the recording and reproducing magnet, as is required. The record having been made, the reproduction Vthereof is accomplished in substantially the usual way, and which does not constitute in itself any particular part of the' present invention. The switch 12 resumes its normal position shown, with blades 12 and 12b in contact so that a direct circuit is formed from magnet 5, through wire Z2, blade 12b, blade 12, receiver 6, wire p, switch blade 15, wire m2, back to the magnet 5; (If switch blade 15 is on the other contact shown, the otherreceiver oramplifier 13 l will be included in this circuit in lieu of the 1. In an apparatus for magnetically re-'l cording and reproducing sound, a magnet,

- and a attery and a tele hone,circuitincludiiig`fsaidlm y K* ai condens rinjseries' with4v one another and bridged o shunted'lracross "said magnet.'4

2, Inan-apparatus "magnetically-re c oi'ding andv reproducing sound, a magnet, a telephone circuit including said,magnet,'

' a battery for said telephone circuit', and a condenser joined toone terminal 4of, said battery so as to be in a series circuit therewith bridged or shunted across said magnet.

3. In an apparatus-for magnetically recording 'and reproducing sound, aymagnet,A

a telephone circuit-including said magnet,

v'cluding said battery and saidzcondenser in vseries with one .another `and bridged or' `4shunted across said magnet.

4,. Inan apparatus for 'magnetically re-V cording and reproducing sound, a `magnet, aftransmitting circuit including said mag' net, and a condenser normally char ed to a` -cuit including a battery, atifansmitter and.

the primary o'r' an induction coil, a secondary circuit includingv the secondary of. said induc; tion coil and a recording land reproducing` magnet, and a condenser formingpart o said seconda circuit.' p

7. In-a te egraphone, aprimary circuit including a battery and transmitter and the 'primaryl ofan induction coil, a secondary circuit including the secondaryT of said coil and a'magnet, a receiver, a switch for linter- Aruptingv said primary circuit and substitutwinding mg said receiver for saidl secondary winding in the secondary circuit, and a' condenser e adaptedto form pa'rt of the secondary cir'- cuit during therecording 'action thereof,

v S-.fIn atelegraphone, a primary circuit 'including 'a batteryl and transmitter and. the primary of an induction coil, a seconda circuit including'` thelsecondaryof -said coil 'I and a magnet, a receiver, a yswitch for interrupting saidprimary circuit and substit uting said recelver :for ,said secondary winding in the seconda circuit, a` condenser; and

means for inclu ing 'said condenserina cir-- cuit in series with said battery' and bridged recording action of the machine.

cuit including a attery, a transmitter` a'nd the prima of an induction coil, a seconda' circuitl inc uding the secondary of said cil' and a magnet, a `condenser lpermanently connected to one terminal of the battery and toa point in said secondary circuit, and a lswitch for closin said ondary circuits an estab shinga separate connection from theother battery terminal to a rpoint in said secondary circuit on the other side of vsaid` magnet andsecondary Ing-,witness-W'hereof, I subscribe my signature, in the presence of two witnesses.

4 l HARVE R. STUART.v

WM, D, COOKE, l Louis WALTERs.-

, 9. In, a telegra hone,a transmitting cir'F-/ lprimary and secfrom said condenser connection 

